kitchen table math, the sequel: 10/19/14 - 10/26/14

Friday, October 24, 2014

Famous last words

Mayor Bill DiBlasio in this morning's Times:

"Ebola is an extremely difficult disease to get."*

Ed read that out loud to me and said, "That's why medical personnel are wearing hazmat suits."

Interestingly, the Times seems to have cut the line. At least, I don't find it on the site now. Found it in the Daily Mail.

I take his point .... which is, I assume, that Ebola is hard to get from a subway seat. (Let's hope so, seeing as how practically everyone I know has been on the subway this week.)

But still.

If you're the mayor, try to get it right.

And stop telling me to remain calm.


*'There is no reason for New Yorkers to be alarmed': De Blasio in desperate appeal for calm over Ebola case... despite news that patient spent a week roaming New York
PUBLISHED: 22:25 EST, 23 October 2014 | UPDATED: 04:19 EST, 24 October 2014

Wednesday, October 22, 2014

Rote understanding

Late to the party ---- I've just read Barry's "Undoing the ‘Rote Understanding’ Approach to Common Core Math Standards"!

I love that phrase: rote understanding.


I was interested to see that Barry was taught "making ten" when he was in grade school:
The “making ten” method is included in the math program used in Singapore—a nation whose fourth and eighth graders have consistently obtained the highest scores in international math tests. Specifically, in Singapore’s Primary Math textbook for first grade, the procedure for adding by “making tens” is explained. Of particular importance, however, is that the procedure is not the only one used, nor are first graders forced to use it. This may be because many first graders likely come to learn that 8 + 6 equals 14 through memorization, without having to repeatedly compose and decompose numbers in order to achieve the “deep understanding” of addition and subtraction that standards-writers—and the interpreters of same—feel is necessary for six-year-olds.

“Making tens” is not limited to Singapore’s math textbooks, nor is it by any means a new strategy. It has been used for years, as it was in my third-grade arithmetic textbook, written in 1955...
I have a question about the teacher's explanation of the number 6:
“So if we can partner 9 to a number and anchor 10, we can help our students see what 9 plus 6 is. So we’re going to decompose our 6, and we know 6 is made up of parts. One of its parts is a 1 and the other part is a 5. 
How do mathematicians think about whole numbers?

Do they see them as "made up of parts"?

Or as decomposable into parts?

(Or both --- ?)

To me, "made up of" and "decomposable into" seem like two different things.

Another question: if 6 is "made up of parts," is 6 one of the parts?

Is 0?

I bet right this minute there are kids all over America who are royally confused by the ramifications of making ten.

Monday, October 20, 2014


We've been to Ireland!

First time ever.

Five days in Dublin --- incredible.

On the way back to the airport, our taxi driver explained the euro, the Germans, and the Irish people's bailout of the banks: "The German banks were in here handing out loans to people they knew couldn't pay them back. It was like going to the races and betting a thousand dollars, and if you won you got $1,040, if you lost you got $1,000."

Neuromyths I have known and loved

In one study Dr. Howard-Jones cites, 48 percent of British teachers agreed with the statement “We mostly only use 10 percent of our brain.” Ninety-three percent believed that “individuals learn better when they receive information in their preferred learning style (for example, visual, auditory or kinaesthetic)” (research actually doesn’t support this), and 29 percent believed “drinking less than 6 to 8 glasses of water a day can cause the brain to shrink” (it can’t). Sixteen percent thought that “learning problems associated with developmental differences in brain function cannot be remediated by education.”

How Brain Myths Could Hurt Kids
I was able to pull the paper, and the data on teacher belief in learning styles is hilarious.

Percentage of teachers who believe individuals learn better when they receive information in their preferred learning style:

93% of teachers in the UK
96% of teachers in the Netherlands
97% of teachers in Turkey
96% of teachers in Greece
97% of teachers in China

Pretty much the entire planetary teaching force.

Sunday, October 19, 2014

Arithmetic for the ages (Ebola v. influenza edition)

Ed and I were chatting about op-eds urging people to forget about Ebola & go get their flu shots, when it occurred to me to wonder how many people actually die of the flu. (Ed had just read an article estimating that with early diagnosis & full supportive care in a Western hospital, the fatality rate for Ebola would be somewhere in the vicinity of 10%.)

Turns out practically nobody dies from the flu:
"Over a period of 30 years, between 1976 and 2006, estimates of flu-associated deaths in the United States range from a low of about 3,000 to a high of about 49,000 people."

Key Facts about Influenza (Flu) & Flu Vaccine
Somebody should check my calculator skills, but using 250,000,000 as the figure for U.S. population I get:

Estimated number of flu fatalities per year: 100 to 1,633
Estimated percent flu fatalities per year: 0.00004% to 0.0007%

I don't know whether the CDC publishes an estimate for how much these numbers were affected by flu vaccine. I'm guessing: not much, seeing as how flu shots aren't particularly effective.

Does anyone know the history of flu shots & the flu shot campaign?

Is there a good reason the entire population is urged to get a flu shot every year?

What am I missing?

For the record, I stopped getting flu shots a few years ago. It's not at all convenient for me to get a flu shot (I used to have to persuade the kids' pediatrician to give me a flu shot, too); the shots hurt; and I always get slightly sick from the shot.

Plus I usually ended up with a wicked case of the flu anyway.

I haven't had the flu since I stopped getting the shot.

Either I'm free-riding on other people's flu shots, or I'm just not getting the flu.

UPDATE: CDC writing lesson & expert raters using holistic scoring rubrics